JP2002056508A - Method for manufacturing contact type magnetic head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a contact type magnetic head free from danger of corrosion of a pad for connection and an electric circuit connected therewith, when a releasing layer is dissolved and removed. SOLUTION: A releasing layer 14 and a first insulating layer 72 are laminated on a substrate 12. Then the surface of the first insulating layer 72 is covered by a mask 74 having a through hole 74a and the first insulating layer 72 is isotropically etched until the first insulating layer 72 laminated directly under the through hole 74a slightly remains. Then the first insulating layer 72 isotropically etched is further anisotropically etched to form a recessed part 76 reaching the releasing layer 14. Then a second insulating layer 78 is laminated on at least the surface of the recessed part 76 and the pad 60 for connection is laminated thereon.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a contact type magnetic head, and more particularly, to magnetic recording of a hard disk, a floppy (registered trademark) disk, a magnetic tape or the like used for a computer, a digital camera, a digital AV or the like. The present invention relates to a method for manufacturing a contact-type magnetic head suitable for high-density recording / reproducing of a medium.

[0002]

2. Description of the Related Art In order to achieve high-density recording / reproduction on a magnetic recording medium such as a floppy disk, a magnetic tape, and a hard disk, an area of the magnetic recording medium in which a leakage magnetic flux generated from a magnetic head is written is reduced. It is necessary to accurately read magnetically recorded information from a minute area. To this end, it is desirable that the magnetic recording medium and the magnetic head be as close as possible. As a magnetic recording / reproducing device developed from such a viewpoint, a contact type magnetic head for recording / reproducing magnetic recording information while directly contacting a contact pad having a magnetic pole with a magnetic recording medium is known.

For example, in Japanese Patent Application Laid-Open No. 8-203190, a magnetic head slider (head chip) is provided with a single contact pad made of diamond, and the tip of the contact pad is provided with a center line average roughness Rmax of 0.5 nm. A contact type magnetic head which is spherically polished to a degree is disclosed.

Japanese Patent Application No. 9-225724 discloses a thin-film head chip having a contact pad (magnetic pole pad) having a magnetic pole (pole chip) and a contact pad for stabilizing the contact running of the magnetic pole pad. The applicant has proposed a contact type magnetic head provided with a plurality of contact pads (auxiliary pads).

FIG. 5C shows an example of the basic structure of a thin-film contact magnetic head provided with contact pads. FIG.
In (c), the contact type magnetic head 50 is provided with a contact pad 59 provided with a pole tip 58 on one surface of a head chip 50a and a bonding pad 60 on the other surface. The head chip 50a includes a magnetic circuit 51, an electric circuit 61, and insulating layers 68a-6
Consists of 8 g.

The magnetic circuit 51 includes a top yoke 52 and bottom yokes 54, 54 made of a magnetic thin film formed substantially parallel to a magnetic recording medium (not shown), and two return studs 56, 56 connecting these. And a pole tip 58 provided at the tip of the bottom yokes 54, 54. A magnetic gap 58a is provided at the tip of the pole tip 58, and a contact pad 59 made of a hard material is provided around the pole tip 58.

The electric circuit 61 includes a bonding pad 60 made of Au, a coil 62, and an up lead 64 connecting the bonding pad 60 and the coil 62. Coil 6
2 is a spiral coil 62 spirally formed in three layers around the left and right return studs 56, 56, respectively.
a ... have a multilayer spiral structure connected to one by interconnects 66, 66 ....

The bonding pad 60 is used to supply a current to the coil 62 from the outside at the time of writing or to extract an induced current flowing to the coil 62 at the time of reading. Coil 62
Is connected to Therefore, although two bonding pads 60 are provided for one head chip 50a, only one of them is shown in FIG. 5C, and the other one is shown in FIG. Has been omitted.

The contact type magnetic head 50 having such a three-dimensional structure is generally manufactured by the following procedure. That is, first, as shown in FIG. 5A, the head chip 50a is
The element plate 10 is manufactured by laminating a release layer 14 for separating the substrate and an element layer 16 including a plurality of head chips 50a. The element layer 16 includes an insulating layer 68 a, a bonding pad 60, a top yoke 52, a coil 62, and the like sequentially laminated on the release layer 14. It is manufactured by forming a contact pad 59 for protecting the chip 58. At this time, thousands to tens of thousands of head chips 50a are formed on the element plate 10 in a connected state.

The bonding pad 60 is part of an electric circuit and is bonded to the beam to support the contact type magnetic head 50. Therefore, the bonding pad 6
The tip of 0 is formed so as to slightly protrude from the surface of the head chip 50a in order to facilitate the bonding between the bonding pad 60 and the beam.

The release layer 14 is provided on the head chip 5.
After the film 0a is formed, it is formed by dissolving and removing it with an etchant to separate the head chip 50a from the substrate 12. Since copper is generally used for the release layer 14 at low cost and easy to form a film, nitric acid is generally used as an etchant. The reason why the tip of the bonding pad 60 is covered with the insulating layer 68a in a state where the head chip 50a is formed on the substrate 12 is to protect the bonding pad 60 from an etchant.

Next, after the entire structure is formed, FIG.
As shown in (b), the groove 1 is formed in the element layer 16 by using a laser.
8 is inserted to separate each head chip 50a. continue,
The head chip 50a is separated from the substrate 12 by etching the release layer 14, and the insulating layer 68
5A, when the portion covering the tip of the bonding pad 60 is removed, the contact type magnetic head 50 shown in FIG.
Is obtained.

[0013]

In order to join the joining pad 60 and the beam and to support the contact type magnetic head by the beam, the joining pad 60 needs to have a certain thickness. Therefore, in order to form the bonding pad 60, a plating method with a high film forming speed is usually used. In this case, since it is difficult to perform plating directly on the insulating layer 68a, it is general to form a metal thin film (plating seed) (not shown) on the insulating layer 68a and use this as one electrode to perform plating. It is a target.

On the other hand, the tip of the bonding pad 60 is covered with the insulating layer 68a having resistance to an etching solution for dissolving and removing the release layer 14, as described above. Therefore, when the release layer 14 is etched, the bonding pad 60 and the electric circuit 61 connected to the bonding pad 60 should not be etched.

However, in the contact type magnetic head 50 manufactured by the above-described method, when the release layer 14 is dissolved and removed, an etching solution may penetrate the insulating layer 68a, and the plating seed may corrode. there were. In addition, when the etching time of the release layer 14 becomes longer, the etching solution may further penetrate into the head chip 50a due to the corrosion of the plating seed, and the electric circuit 61 may be corroded.

An object of the present invention is to provide a method of manufacturing a contact-type magnetic head in which a bonding pad and an electric circuit connected thereto are not likely to be corroded when a release layer is dissolved and removed. .

[0017]

In order to solve the above-mentioned problems, a method of manufacturing a contact type magnetic head according to the present invention comprises a release layer laminating step of laminating a release layer on a surface of a substrate, and a step of laminating the release layer. A first insulating layer laminating step of laminating a first insulating layer on the surface of the substrate,
A first etching step of forming a concave portion in which the bottom surface and the side wall portion are connected by a gentle curve in the first insulating layer; and anisotropically etching the concave portion until the tip of the concave portion reaches at least the release layer. Etching step, a second insulating layer laminating step of laminating a second insulating layer on at least a surface of the concave portion, and a pad for laminating a bonding pad on the concave portion on which the second insulating layer is laminated. The gist of the present invention is to include a laminating step.

In the first etching step, a recess is formed in the first insulating layer in which the bottom surface and the side wall are connected by a gentle curve, and the recess is further anisotropically etched. When it reaches the release layer, it has no corners at its tip and its periphery is gently inclined. When the second insulating layer is formed on the concave portion, the thickness of the second insulating layer becomes substantially uniform, and the resistance to the etching solution for etching the release layer is improved.

[0019]

Embodiments of the present invention will be described below in detail with reference to the drawings. 1 and 2
1 shows a process chart of a manufacturing method according to an embodiment of the present invention. In the present invention, the contact magnetic head is manufactured by the following procedure. That is, as shown in FIG. 1A, first, the release layer 14 is laminated on the substrate 12 (release layer laminating step), then, the intermediate layer 70 is laminated on the release layer 14, and further thereon. First insulating layer 72
Are laminated (first insulating layer laminating step).

Here, the substrate 12 is for supporting a contact type magnetic head laminated thereon, and its material is not particularly limited. Generally, Al ₂
O _{3, Al} 2 _O 3 ceramic substrate such as -TiC is used.

The release layer 14 is for separating the head chip from the substrate 12 after all the structures are stacked on the substrate 12. Therefore, a metal material (eg, copper, chromium, nickel, or the like) that is inexpensive and easy to remove with an etchant is generally used for the release layer 14. The thickness of the release layer 14 can be arbitrarily determined in consideration of a film formation rate, a dissolution rate by an etchant, and the like. Usually, it is several μm to several tens μm.

The first insulating layer 72 protects a magnetic circuit and an electric circuit formed inside the contact type magnetic head, and at the same time, serves as a main structural material constituting the outermost surface of the contact type magnetic head. It is made of a material having an insulating property. Generally, ceramic materials such as alumina and silica are used. The thickness varies depending on the structure of the contact type magnetic head to be manufactured, but is usually about several μm.

The intermediate layer 70 is laminated to improve the adhesion between the release layer 14 and the first insulating layer 72. Therefore, when good adhesion is obtained between the release layer 14 and the first insulating layer 72, the intermediate layer 70 is not always necessary. The material and thickness of the intermediate layer 70 are
According to the material of the release layer 14 and the first insulating layer 72, the material and the thickness are set so as to obtain good adhesion. For example, when copper and alumina are used as the release layer 14 and the first insulating layer 72, respectively, a good adhesion cannot be obtained if both are directly laminated, so that the intermediate layer 70 has a thickness of about 150 nm between the two. It is preferable to laminate a Cr layer.

The method of forming the release layer 14, the intermediate layer 70, and the first insulating layer 72 is not particularly limited, and an optimum one is selected in consideration of the material, the film forming speed, and the like. Good to do. Further, depending on the method for forming the release layer 14, the intermediate layer 70, or the first insulating layer 72, irregularities may be generated on the surface of the first insulating layer 72. In such a case, it is preferable to polish the surface of the first insulating layer 72 after the first insulating layer 72 is stacked.

Next, a concave portion in which the bottom surface and the side wall portion are connected by a gentle curve is formed in the first insulating layer 72 by etching (first etching step). Specifically, FIG.
As shown in (b), a mask 74 having a through hole 74a
Is used to cover the surface of the first insulating layer 72 (mask process),
Next, as shown in FIG. 1C, isotropic etching may be performed on the first insulating layer 72 covered with the mask 74 (first etching step). Thereby, a concave portion 76a having a predetermined shape is formed in the first insulating layer 72.

The material of the mask 74 is the first material described later.
What is necessary is just to have resistance to the etching in the etching step, and there is no particular limitation. Usually, a photoresist film is used.

Further, the isotropic etching is performed until the first insulating layer 72 laminated immediately below the through hole 74a of the mask 74 slightly remains, and the release layer 14 (the intermediate layer 70) is formed.
Is stacked, the etching must be stopped before the intermediate layer 70) is completely exposed.

In this case, it is not preferable that the remaining thickness of the first insulating layer 72 is too large because it takes a long time to remove the first insulating layer 72 in a second etching step described later. On the other hand, if the remaining thickness of the first insulating layer 72 is too small, the release layer 14 or the intermediate layer 72 may be exposed due to a slight change in etching conditions, which is not preferable. The optimum remaining thickness differs depending on the thickness, material, and the like of the first insulating layer 72 when the first insulating layer 72 is formed. For example, when the first insulating layer 72 is made of alumina having a thickness of about 5 μm, the remaining thickness is 1
About μm is preferable.

Specific examples of the isotropic etching include a wet etching method using an etching solution, a plasma etching method for causing a chemical reaction with radicals generated by electric discharge, and the like. In the first etching step, May be used, and the first insulating layer 7
An optimum method may be selected according to the material, cost, etc. However, since the plasma etching method has a low etching rate and is expensive, it is preferable to use a wet etching method in the first etching step. In this case, an optimum etchant may be selected depending on the material of the first insulating layer 72. For example, the first
When the insulating layer 72 is made of alumina, the etching solution includes
Preferably, phosphoric acid is used.

Next, after removing the mask 74, anisotropic etching is further performed on the isotropically etched first insulating layer 72 (second etching step). Here, specific examples of the anisotropic etching include ion beam etching, reactive ion etching, and the like. In the second etching step, any method may be used. An optimum method may be selected according to the material, cost, and the like of the release layer 14. For example, when the first insulating layer 72 and the release layer 14 are made of alumina and copper, respectively, the ion beam etching method is preferable.

When the anisotropic etching is performed with the mask 74 removed, the first insulating layer 72 is first etched. As the etching further proceeds, the bottom portion of the concave portion 76a whose film thickness has been reduced by the isotropic etching is completely removed, and the release layer 14 (or the intermediate layer 70) is exposed. Since the release rate of the release layer 14 is generally higher than that of the insulating layer 72, the release layer 14 is preferentially etched thereafter.
After a lapse of a predetermined time, a concave portion 76 having a predetermined depth is formed in the release layer 14 as shown in FIG. The concave portion 76 obtained by such a method has no corner at the tip, and has a shape in which the side wall portion is gently inclined.

Next, after the concave portion 76 reaching the release layer 14 is formed, as shown in FIG. 1E, a second insulating layer 78 is formed on the surface of the concave portion 76 (second insulating layer forming step).
In this case, the second insulating layer 78 only needs to be formed at least on the surface of the concave portion 76, but is formed over the entire surface of the first insulating layer 72 and the concave portion 76 as shown in FIG. Is also good. The same material is usually used for the second insulating layer 78 and the first insulating layer 72, but different materials may be used. Note that the first insulating layer 72 and the second insulating layer 78
This corresponds to the insulating layer 68a shown in FIG.

Next, as shown in FIG. 2A, a plating seed 80 is formed on the second insulating layer 78. The material, thickness, forming method, and the like of the plating seed 80 are selected optimally according to the material of the bonding pad, plating conditions, and the like.
For example, when Au is used as the material of the bonding pad,
The plating seed 80 is preferably a NiFe thin film having a thickness of about 100 nm formed by a sputtering method.

Next, after forming a mask (not shown) having an opening corresponding to the bonding pad on the plating seed 80, the bonding pad is formed by plating using the plating seed 80 as one electrode. (Pad layer laminating step). FIG. 2B shows a state in which the bonding pad 60 is formed on the plating seed 80. Note that various materials can be used as the material of the mask for forming the bonding pad 60, and the material is not particularly limited. Usually, a photoresist film is used.

Next, as shown in FIG. 2C, an up lead 64 is formed on the bonding pad 60, and a part of a magnetic circuit and an electric circuit (not shown) is laminated.
These are covered with an insulating layer 68b as shown in FIG.

The subsequent steps are the same as in the conventional manufacturing method. That is, an electric circuit such as a coil and a return stud and a magnetic circuit are sequentially stacked on the insulating layer 68b.
Next, after a cut is made along the boundary of the head chip, the release layer 14 is dissolved and removed to separate the head chip. Further, the second insulating layer 78 covering the tip of the bonding pad 60 is removed. As a result, a contact-type magnetic head in the form of a thin film having contact pads on one surface of the head chip and bonding pads on the other surface is obtained.

Next, the operation of the method for manufacturing a contact type magnetic head according to the present invention will be described. Since the tip of the bonding pad is covered with the insulating layer, the electric circuit inside the head chip should not be corroded when the release layer is dissolved and removed by the etchant. However, in some of the obtained contact magnetic heads, the electric circuit was corroded. When the cause was examined in detail, it was found that the shape of the concave portion for forming the bonding pad 60 had a cause.

That is, when the concave portion for forming the bonding pad 60 is formed by etching after the release layer 14 and the first insulating layer 72 are laminated on the substrate 12, the release layer 14 and the first insulating layer 72 are formed. Since the materials are different, the etching is performed twice. Generally, isotropic etching, particularly low-cost wet etching, is used for etching the first insulating layer 72, and anisotropic etching is used for etching the release layer 14.

In the case where the first insulating layer 72 is wet-etched, as shown in FIG. 3A, a method of covering the surface with a mask 74 having a through hole 74a and dipping the entire substrate 12 in an etching solution. Is adopted. At this time, the first insulating layer 72 immediately below the through hole 74a is etched substantially parallel to the surface. Further, as the etching of the first insulating layer 72 immediately below the through hole 74a progresses,
Since the etchant flows under the mask 74, the first insulating layer 72 below the mask 74 and near the through hole 74a is also etched.

As a result, when the first insulating layer 72 immediately below the through hole 74a is etched by the thickness x, the mask 74 is removed.
In the lower part, an arc-shaped region having a radius x from the end of the through hole 74a is etched. At the time when the first insulating layer 72 having the thickness t stacked immediately below the through-hole 74a is completely removed, the radius of the arc-shaped region below the mask 74 is substantially equal to t (hereinafter, this is referred to as “t”). The state is called "just etch".) When the wet etching is further continued, the etching area below the mask 74 expands in the lateral direction (hereinafter, this state is referred to as “overetch”).
That. ).

On the other hand, the release layer 14 and the first insulating layer 72
In, respectively, copper and alumina are usually used,
The etching rate by anisotropic etching generally differs depending on the material. For example, when ion beam etching is used as anisotropic etching, the etching rate of alumina is about half that of copper. Therefore, when forming a recess in the release layer 14 by anisotropic etching after performing isotropic etching,
If the first insulating layer 72 remains, it takes a long time to remove it. In addition, since there is an unavoidable change in the etching conditions, stopping the isotropic etching in the just-etched state may cause the first insulating layer 72 to remain undissolved.

Therefore, in order to avoid this, it is necessary to perform the isotropic etching until the over-etched state is reached to completely expose the release layer 14. However, when the overetching is performed, when the isotropic etching is completed, as shown in FIG.
2 and the exposed release layer 14
An angle θ (θ> 0) is generated between the surface and the surface.

When anisotropic etching is performed in this state, as shown in FIG. 3B, a corner 77a is formed at the tip of the concave portion 77 formed in the release layer 14. Further, the angle of the side wall of the concave portion 77 rises steeply. When the second insulating layer 78 is stacked in such a concave portion 77, as shown in FIG. 3C, a fragile layer 77b is formed at the corner 77a,
Further, a thin portion 77c is formed near the boundary between the first insulating layer 72 and the release layer 14. As a result, when the release layer 14 is etched, the etching solution
b and / or the thin portion 77c may be transmitted to reach the bonding pad, and the electric circuit may be corroded by the etchant.

On the other hand, as shown in FIG. 4 (a), when the first insulating layer 72 is isotropically etched, the release layer 14 is not completely exposed and is directly under the through hole 74a of the mask 74. When the laminated first insulating layer 72 slightly remains, when the isotropic etching is stopped,
No angle θ occurs between the bottom surface and the side wall of the concave portion 76a formed in the first insulating layer, and the bottom surface and the side wall are connected by a gentle curve.

When the concave portion 76a having such a shape is subjected to anisotropic etching, no corner is generated at the tip of the concave portion 76 reaching the release layer 14, as shown in FIG. Also, the first insulating layer 72 and the release layer 14
Has a gentle slope in the vicinity of the boundary. When the second insulating layer 78 is laminated thereon, as shown in FIG. 4C, the thickness of the second insulating layer 78 becomes substantially uniform, and no fragile layer or thin portion is generated. As a result, when the release layer 14 is removed by etching, the etchant does not pass through the second insulating layer 78 and reaches the bonding pad 60, thereby preventing corrosion of the electric circuit by the etchant.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above embodiments, and various modifications are possible without departing from the gist of the present invention. is there.

For example, in the above embodiment, an example in which the present invention is applied to a contact type magnetic head having a magnetic pole pad has been mainly described. However, the present invention relates to a contact magnetic head having both a magnetic pole pad and an auxiliary pad. The same can be applied to the manufacture of a magnetic head.

In the above-described embodiment, in the first etching step, isotropic etching, in particular, low-cost wet etching is used to form the first insulating portion 76a in which the bottom and the side wall are connected by a gentle curve. Although formed in the layer 72, the method of forming the concave portion 76a having such a shape is not limited to this. For example, even when the anisotropic etching is used as the etching method in the first etching step, if the etching conditions, particularly the beam irradiation angle, are optimized, a shape substantially similar to the case using the isotropic etching is obtained. The first concave portion 76a having
It can also be formed on the insulating layer 72.

[0049]

According to the method of manufacturing a contact type magnetic head according to the present invention, when a concave portion for forming a bonding pad is formed by etching, first, a concave portion in which a bottom surface and a side wall portion are connected by a gentle curve. Is formed in the first insulating layer, and then the recess is further subjected to anisotropic etching, so that the thickness of the second insulating layer laminated on the recess is made substantially uniform. Can be the second
This has the effect of improving the resistance to the etchant when dissolving and removing the release layer of the insulating layer. This also has the effect of preventing corrosion of the bonding pad and the electric circuit connected to the bonding pad when etching the release layer.

[Brief description of the drawings]

FIG. 1 is a process chart showing a method for manufacturing a contact type magnetic head according to the present invention.

FIG. 2 is a continuation of the process chart shown in FIG. 1;

FIG. 3 is a diagram illustrating a change in the shape of a concave portion due to a difference in an etching method.

FIG. 4 is a diagram illustrating a change in the shape of a concave portion due to a difference in an etching method.

FIG. 5 is a process chart showing a method for manufacturing a conventional contact magnetic head.

[Explanation of symbols]

 12 Substrate 14 Release Layer 50 Contact Magnetic Head 60 Bonding Pad 72 First Insulating Layer 74 Mask 74a Through Hole 76 Depression 78 Second Insulating Layer

Claims (2)

[Claims] An etching method comprising: a release layer laminating step of laminating a release layer on a surface of a substrate; a first insulating layer laminating step of laminating a first insulating layer on a surface of the substrate on which the release layer is laminated; A first etching step of forming a concave portion in which the bottom surface and the side wall portion are connected by a gentle curve in the first insulating layer; and anisotropically etching the concave portion until at least a tip of the concave portion reaches the release layer. A second etching step of laminating a second insulating layer on at least the surface of the recess.
A method for manufacturing a contact type magnetic head, comprising: an insulating layer laminating step; and a pad laminating step of laminating a bonding pad on the concave portion where the second insulating layer is laminated. 2. The first etching step includes a mask step of covering the surface of the first insulating layer using a mask having a through hole, and the first insulating layer laminated immediately below the through hole slightly remains. 2. The method according to claim 1, further comprising an isotropic etching step of isotropically etching the first insulating layer until a state is reached.